Hydroxyl containing liquid mercaptan-terminated acrylate polymers

ABSTRACT

LIQUID MERCAPTAN-TERMINATED ACRYLATE POLYMERS CONTAINING PENDANT HYDROXYL GROUPS ARE OBTAINED BY PREPARING AN INTERMEDIATE POLYMER OF AN ALKYL ACRYLATE (A) WITH A WITH A VINYLIDENE ($C=CH2) MONOMER CONTAINING A HYDROXYL GROUP IN THE PRESENCE OF A DIXANTHOGEN DISULFIDE, AND THEN HYDROLYZING OR PYROLYZING THE INTERMEDIATE POLYMER TO FORM MERCAPTAN GROUPS, (B) WITH VINYL ACETATE IN THE PRESENCE OF A DIXANTHOGEN DISULFIDE, AND THEN HYDROLYZING THE ACETATE GROUPS TO FORM HYDROXYL GROUPS EITHER PRIOR TO OR AFTER FORMING THE MERCAPTAN GROUPS, AND (C) WITH A VINYLDENE MOMOMER CONTAINING AN EPOXIDE   (-CH2&lt;(-O-CH2-))   GROUP IN THE PRESENCE OF A DIXANTHOGEN DISULFIDE, AND THEN REACTING THE EPOXIDE GROUP WITH AN ALCOHOL TO INTRODUCE HYDROXYL GROUPS EITHER PRIOR TO OR AFTER FORMING THE MERCAPTAN GROUPS. THE POLYMERS CURE AT APPLICATION TEMPERATURES AND HAVE LOW TEMPERATURE EXTENSIBILITY, MAY BE FORMED INTO CAULKS, SEALANTS, POTTING COMPOUNDS AND ADHESIVES.

'U.S. Cl. 260-79 United States Patent Ofice 3,711,451 HYDROXYL CONTAINING LIQUID MERCAPTAN- TERMINATED ACRYLATE POLYMERS Alan A. Csontos, Norton, Ohio, assignor to The B. F.

. Goodrich Company, New York, N.Y.

N Drawing. Filed May 12, 1971, Ser. No. 142,808

Int. Cl. C08d 3/02 10 Claims ABSTRACT OF THE DISCLOSURE L iquid mercaptan-terminated acrylate polymers contaming pendant hydroxyl groups are obtained by preparmg an intermediate polymer of an alkyl acrylate (a) with a with a vinylidene C=CH monomer containing a hydroxyl group in the presence of a dixanthogen disulfide,

and then hydrolyzing or pyrolyzing the intermediate p0lymet to form mercaptan groups, (b) with vinyl acetate in the presence of a dixanthogen disulfide, and then hydrolyzing the acetate groups to form hydroxyl groups either prior to or after forming the mercaptan groups, and (c) with a vinylidene monomer containing an epoxide group in the presence of a dixanthogen disulfide, and then reacting the epoxide group with an alcohol to introduce hydroxyl groups either prior to or after forming the merc'aptan groups. The polymers cure at application temperatures and have low temperature extensibility, may be formed into caulks, sealants, potting compounds and adhesives.

BACKGROUND OF THE INVENTION Acrylate elastomers possess good weatherability and oil resistance. These properties are advantageous in base polymers used in sealants, caulks, and like formulations. However, for ease of application, the sealant or caulk must be pourable at application temperatures, or extrudable as e from a tube, or moldable under slight pressure. This can .be attained either by dissolving a solid acrylate elastomer ,m a suitable solvent or by using a low molecular weight -meet this, alkyl acrylateswherein thealkyl group contains three or more carbon atoms are used to provide polymers having a Tg (glass transition temperature) of below -26 C. However, when these elastomers are vulcanized, they often are slow to cure and have an objectionable tackyfsurface.

SUMMARY OF THE INVENTION This invention provides acrylate polymer compositions,

pourable at application temperatures, having aTg value below 15 F. (-26" C.), having terminal meroaptan groups and pendant hydroxyl groups, that are readily cured at application temperatures to a substantially tackfree. surface.

DETAILED DESCRIPTION Liquid 'mercaptan-terminated, pendant hydroxyl acrylate polymers containing about 0.1 to 10 Weight percent" Patented Jan. 16, 1973 hydroxyl and about 0.5 to 10 weight percent mercaptan groups can be prepared by several processes.

The pendant hydroxyl groupscan be introduced into the polymer by polymerizing together alkyl acrylate monomers with vinylidene C=CH monomers containing hydroxyl groups in the presence of a dixanthogen disulr fide. Typical hydroxybcontaining vinylidene monomers are methallyl alcohol, hydroxy butyl vinyl ether, and ortho-, meta-, and paravinyl benzyl alcohol. To obtain the desired polymeric Tg and hydroxyl content, amounts 0.5 part to.30 parts by weight of methallyl alcohol, about 0.5 part to 60 parts by weight of hyd'roxybutyl vinyl ether, and about 1 part to 50 parts by weight of o-, mand p-vinyl benzyl alcohol based on 100 partsof total monomer charged. The mercaptan groups are formed by hydrolyzing or pyrolyzing the xanthate groups.

The defined polymer can also be obtained by first preparing an intermediate polymer by polymerizing together alkyl acrylate monomers with vinyl acetate in the pres' ence of a dixanthogen disulfide as the polymerization modifier. Amounts of vinyl acetate used to obtain the desired polymer are from about 0.5 part to37 parts by weight based upon 100 parts of total monomer charged. The hydroxyl groups are then formed by hydrolyzing the acetate groups with potassium hydroxide llll ethanoh. This may be done prior to or after the hydrolysis or pyrolysis of the Xanthate groups to form the mercaptan groups.

The defined polymesr are readily obtained by first preparing an intermediate polymer by polymerizing together alkyl acrylate monomers with vinylidene monomers congroupsin the presence of a dixanthogendisulfide as the polymerization modifier. The e'poxide groups are then reacted with an alcohol in the presence of a mineral acid .catalyst to introduce the pendant hydroxyl groups. This structure R H2 0: J3

group containing 1 to 18 carbon atoms, or an ether group where the total number of canbon atoms does not eXceedS.

The acrylates may be used singly or in combination to' obtain polymers having in their cured state a Tg value below 26 C. Typical acrylates are ethyl acrylate, n-bu'tyl acrylate, isobutyl acrylate, n-hexyl acrylate, Z-methylhexyl acrylate, methyl methacrylate, n-butyl methacrylate, n-

oct'yl methacrylate, n-octadecyl methacrylate, "ethyl ethacrylate, methoxy ethyl acrylate, ethoxy propyl acrylate, and thelike. Useful compositions include at least 13 parts by weight of an alkyl acrylate where the R groupis H, and the R group is an alkyl croup containing 3 to 8'carbon atoms with ethyl acrylate, based on 100 parts by weight of total alkyl acrylate. One useful composition contains about 20 and 40 parts by weight of ethyl acrylate and about 60 to partsby Weight of normal butyl acrylate based on parts by Weight of alkyl acrylates.

i In place of part of the alkyl acrylates, other vinylidene monomers'may be used as long as the polymeric Tg is not higher than 26 C. Typical vinylidene monomers which may be used are up to about parts by weight of acrylonitrile, styrene, and tat-methyl styrene; about 20 to 30 parts of vinyl ethers, such as vinyl methyl ether, vinyl ethyl ether, and vinyl n-butyl ether and vinyl ketones, such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropenyl ketone; and the like.

The epoxide-containing vinylidene monomers are used in the range of from about 2 to 20 parts by weight, based upon 100 parts by weight of the alkyl acrylates, to obtain the desired hydroxyl content in the polymer. Typical epoxide-containing vinylidene monomers are the vinylidene glycidyl/ esters such as glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate,'and the like, and the vinylidene glycidyl etherssuch as allyl glycidyl ether, methallyl 'glycidyl ether, isopropenyl glycidy ether, and the like. The preferred epoxide-containing monomer isglycidyl acrylate as it copolymerizes fast and eificiently with the alkyl acrylate monomers. The preferred range of glycidyl acrylate used is about 3 to 10 parts by weight based on 100 parts by weight of alkyl acrylates.

The mercaptan groups are introduced into the polymer by the use of dixanthogen disulfides as the initiator and/or modifierin the polymerization of the monomers. This results in terminal xanthate groups which when reacted in a base catalyzed hydrolysis using an agent such as KOH, or under conditions of pyrolysis, form terminal mercaptan groups. The dixanthogen disulfides employed correspond to the general formula where R may be an alkyl group of 1 to 8 carbon atoms, an aryl group such as phenyl, an aralkyl .group such as benzyl, and an alicyclic group such as cyclohexyl. Typical dixanthogen disulfides are -diisopropyl xanthogen disulfide, disecondary butyl xanthogen disulfide, di(B-naphthyl) xanthogen disulfide, anddicyclohexyl xanthogen disulfide. Preferred dixanthogen disulfides are the alkyl dixanthogen disulfides where the alkyl group contains 3 to 6 carbon atoms. The dixanthogen disulfides are used in the range from about 2 parts to '20 parts by weight based on 100 dissolve the dixanthogen disulfide in the alkyl acrylate monomer(s) or the solvent if used. The reactor vessel is then purged with nitrogen and sealed. Polymerization temperatures used range from about 20 C. to about 100 C. A preferred temperature range is from about 40 C. to about 60 C. v

The UV light must be allowed to penetrate to the polymerization solution. This can'be accomplished by placing the UV source within a glass tube in the reactor or by having the UV source external to the reactor vessel with the UV light passing through a glass wall or window to the solution. Any lamp generating near UV light, especially in the range of 3000 A. to 4000 A. may be used. Lamp types and their emission spectra and glass types and their transmission spectra are known to those skilled in the art.

Polymerization is initiated by turning on the UV light source and is stopped by turning oil? the source. Percent conversion of monomers to polymer is easily followed by taking percent total solids samples. Over 60% conversion of monomers to polymer is desirable.

The xanthate-terminated liquid acrylate polymer is recovered from solution by heating the polymerization solution under vacuum to distill off the remaining monomer(s) and solvent if used. Drying temperatures used range from about 70 C. to 130 C., with 90 C. being a convenient temperature.

Pendant hydroxyl groups are readily obtained by reacting the pendant epoxide group of the Xanthateor mercaptan-terminated polymer with an alcohol in the presence 7 of a catalyst such as a mineral acid. A solvent may be parts of the alkyl acrylates. A more. preferred range is from about 4 to 12 parts by weight. I

' Employing amounts of alkyl acrylate, vinylidene monomer containing epoxide groups, and dixanthogen disulfide as stated above, and polymerizing the monomers together in the presence of a dixanthogen disulfide to above 60% employing those ingredients and polymerization conditions knownto the art. Eitherthedixanthogen disulfide used alone or used with free-radical catalysts initiates-polymerization. Typical free radical catalysts that can be used are organic peroxides and hydroperoxides, persulfates,'azo

compounds, and the use .of redox systems. One preferred method is to use the dixanthogen disulfide alone without violet (UV) light to dis-associate the dixanthogen disulfide into free-radicals which initiate polymerization. In this manner the-.dixanthogen disulfides function both as initiators and modifiers. This method is best employed in bulk or solution polymerization.

The UV polymerization of the xanthate-terminated liquid. acrylate polymer is easily performed. The alkyl acrylate .monomer(s), the epoXide-containing vinylidene monomer and the dixanthogen disulfidef are charged to a reactor vessel alongwith a'solvent if used. No: specific o der of ch g g r q re but itis p efe able to pre- .the use of further free-radical catalysts, and to use ultraused. Typical solvents are benzene, toluene, and hexane.

The mineral acid may be any of the strong inorganic acids.

may also be employed where the n20 and no larger than 10, and the R group may be a radical of the formula C I-I where x=l to 10, or an ether, thioether, or a keto ne wherein the total number of carbon atoms does not exceed 10. The preferred alcohols are the polyhydric alcohols'of the general formula cHr-oH Hy-OH where n=0 to 10. These alcohols are commonly referred to as diols. Typical diols are ethylene glycol, propylene glycol, 1,4-butanediol and 1,8-octanediol.

The amount of alcohol used is based on the amount of 'epoxide in the polymer. This may be measured by determining the epoxide equivalents in the polymer, the grams of polymer containing one epoxy group. A more convenient method is to base the amount of alcohol used on theamount of .epoxide-containing vinylidene monomer that was used in the polymerization. Levels of alcohol used range from about 0.1 mole of hydroxyl per 1 mole of epoxide to about '5 moles of hydroxyl per mole of epoxide. A preferred level is to use about one mole excess ofhydroxyl to every mole of epoxide. Amounts of hydroxyl used in excess of fivemoles per mole of epoxide to react with the epoxide group are not necessary.

Themineral-acid and alcohol are charged to the liquid ac y a p ym r and the solvent in the reactor vessel. The

vessel is then sealed. The reaction takes place under agitation in the temperature range of about C. to about 150 C. 90 C. is a convenient temperature to use.

The pendant hydroxyl liquid acrylate polymer is recovered by putting the solution under vacuum and raising the temperature to 150 C. if needed to distill otf the unreacted alcohol and solvent if used. If the alcohol boils between 150 C. and 220 C. under vacuum, and the xanthate-terminated form of the polymer was used, the alcoholcan be distilled 01f during the pyrolysis procedure used to form the mercaptan groups. The polymer may also be recovered by using a methanol/water coagulation followed by drying at 90 C. under vacuum.

These polymers can also be obtained by first preparing vinylidene monomers containing hydroxyl groups by reacting theepoxide-containing vinylidene monomers described above with a diol following the procedure as given for the reaction of the epoxide-containing liquid polymers, and then polymerizing together the prepared monomer with alkyl acrylatesin the presence of a dixanthogen disulfide. For example, the reaction product of glycidyl acrylate with 1,4-butanediol is l-hydroxyl butoxy-Z-hydroxylpropyl acrylate. This hydroxyl-containing vinylidene monomer can be polymerized together with the above stated alkyl acrylates to yield the desired polymers.

Employing the alcohols and the procedure as stated above, and using the pendant epoxide liquid acrylate polymers yields pendant hydroxy l liquid acrylate polymers containing about 32 percent to about 96 percent by weight of alkyl acrylates and about 3 percent to about 60 percent by weight of the structure thereby having hydroxyl contents ranging from about 0.1% to 10% by weight all weights based on the total weight of polymer. More preferred, the polymer contains from about 1% to about 53% by weight of ethyl acrylate, about 13% to about 95% by Weight of an alkyl acrylate 0f the formula CH CH-COOR wherein R is an alkyl group containing 3 to 10 carbon atoms about 1% to about 4% by weight of mercaptan groups and about 3% to about 30% by Weight of the structure wherein R is a radical of the formula C H where x is 2 to 6. The preferred level of hydroxyl content is from about 0.5% to 5% by weight. It is possible following the procedure of this invention for epoxide groups to remain unreacted and pendant to the polymer.

Whether the hydroxyl-containing vinylidene monomers prepared by reacting glycidyl acrylate or glycidyl methacrylate with a diol are used as co-monomers with alkyl acrylates in the polymerization of the liquid polymers, or the epoxide groups of liquid polymers prepared by using glycidyl acrylate or glycidyl methacrylate as co-monomers in the polymerization are reacted with a diol after polymerization, the structure obtained is Where R is -H or -CH and R'" is a radical of the formula C H where x is 2 to 10, an ether, a thioether, or a ketone wherein the total number of carbon atoms does not exceed 10.

Other groups in addition to hydroxyl groups may be added pendant to the acrylate polymer by reaction with the epoxy group following the above procedure. Such groups include olefinic groups formed by reacting the epoxide group with hyroxy butyl vinyl ether, methallyl alcohol, and the like; carboxyl groups by using glycollic acid, malic acid, and the like; mercaptan groups by using thioglycerol and the like; and halogen groups by using glyceryl monoand dichlorohydrin and the like.

The xanthate-terminated liquid acrylate polymers can be treated to form mercaptan groups by the hydrolysis of the xanthate groups under the action of a base such as KOH or by the pyrolysis of the xanthate groups. The hydrolysis method requires a solvent media for both the polymer and the base. This means more ingredients and another recovery step. The preferred method therefore is the bulk pyrolysis method. In this method, the xanthateterminated liquid acrylate polymer is charged into a reactor vessel and heated to above C. under vacuum. A useful temperature range is from about 130 C. to 260 C., whereas a temperature range of about 160 C. to 220 C. is'more preferred. The pyrolysis may be performed in a batch or a continuous process. The time of pyrolysis varies inversely with temperature, varying from about 10 hours at C. to about 20 seconds at 250 C. A useful batch pyrolysis condition is 20 minutes at 200 C. The breakdown of the xanthate groups is performed under a vacuum to rid the reactor vessel of gaseous carbonyl sulfide and the alkene derivative of the xanthate R group which are given 011 as by-products.

The mercaptan-terminated liquid acrylate polymers are recovered as bulk products. The mercaptan level on these compositions ranges from about 0.5 by weight to about 8% by weight based on the weight of the polymer. The preferred level is from about 1% to 4% by weight.

The liquid mercaptan-terminated acrylate polymers containing pendant hydroxyl groups are characterized by having a bulk viscosity as measured at 27 C. using a Brookfield model LVT viscometer with spindle #7 at 20 rpm. in the range of from about 400 cps. to 2,000,000 cps. A convenient range for many applications is from about 5,000 cps. to about 150,000 cps.

The mercaptan-terminated liquid acrylate polymers containing pendant hydroxyl groups are stable at application temperatures. The polymers may be mixed with compounding ingredients on ink mills, bulk mixing equipment such as Henschel mixers, and the like. Compound ingredients useful in liquid polymers known to those skilled in the art may be used. Typical ingredients are fillers such as clays, T102, carbon black, silicas, and the like; lubricants and plasticizers; stabilizers and antioxidants and pigments.

Cure agents for the mercaptan-terminated liquid polymers are selected from oxidizing agents such as PbOg, PbO in the presence of an organic acid such as acetic acid, tertiary butyl perbenzoate, and organic and inorganic peroxides; diand trifunctional acrylates such as trimethylol propane triacrylate employing an amine catalyst; diisocyanates such as tolylene diisocyanate, 4,4'-diisocyanato diphenyl methane, and the like; and epoxy resins and epoxy Novalac resins both employing an amine catalyst. Epoxy resins" such as diglycidol ethers of Bisphenol A employing an amine catalyst are the preferred curati-ves. Typical amine catalysts are 2,4,6-tri(dimethylaminomethyl)phenol and triethylene tetraamine.

The mercaptan-terminated liquid acrylate polymers containing pendant hydroxyl groups can be cured to a tack-free surface at application temperatures. This combined with their low Tg value and their good weatherability and oil resistance, make these polymers useful.

base elastomers for sealant, caulk, and like compounds.

The following examples will further illustrate the invention. In the examples, the amounts of ingredients are expressed in parts by weight unless otherwise stated.

7 7 EXAMPLE I Xanthate-terminated liquid acrylate polymers containing pendant epoxide groups were prepared as described below. The recipes and polymerization data were:

Ethyl acrylate. Normal butyl acrylat Glycidyl acrylate 5 3 5.

Diisopropyl xanthogen disulfide 8 8 8 Irradiation time, hours Temperature, C Percent conversion- The ingredients were charged to a glass reactor vessel;

15 3. I 3 3 X X Grams of xanthate-terminated polymer Grams, lA-butanediol Grams, 38% cone. HCl Milliliters toluene Bulk viscosity, cps. at 27 C. Weight percent mercaptan Weight percent hydroxyl The bulk viscosities were measured with a Brookfield model LVT viscometer using spindle #7 at r.p.m. Mercaptan content was determined by iodineoxidation andhydroxyl content determined by caustic titration to an end point.

EXAMPLE II The polymers prepared in Example I were cured according to the following recipes:

Mercaptan-terminated pendant OH polymen DMP- 0 Epon 828 Cure 4 days at room temperature Hardnessi Durometer A Percent elongation 1 2,4,6-tri (dimethylaminomethyl)phenol. Z Diglycidol ether of Bisphenol A. a Instantaneous hardness/hardness after 10 seconds.

EXAMPLE III An xanthaJte-terminated liquid acry late polymer having no pendant hydroxyl groups was prepared following the procedure of Example I. The recipe used was parts of ethylacrylate, 70 parts of normal butyl acrylate, and 6 parts of diisopropyl xanthogendisulfide. 97% conversion was obtained in four-hours of irradiation. Thebulk polymer had a viscosity of 17,000cps. at.27 C. as meas-. ured by a Brookfield model LVT viscometer using spindle #7'at 20 r.p.m. The polymer was pyrolyzed by raisingthe temperature to 200 C. for-20 minutes while undera vacuum. The mercaptan-terminated liquid acrylate had a 23,400 cps. bulk viscosity at 27 C. and a weight percent mercaptan content of 1.52%. The. polymer was then cured according to the following recipe:

Mercaptan-terminated polymer having no hydroxyl groups DMP-30 1.0 Epon 828 16.

There was no evidence of cure in one day and the polymer had a tacky surface after 7 days at room temperature EXAMPLE IV A mercaptan-terminated pendant hydroxyl liquid acrylate polymer was prepared following the procedure of Example I. The polymer had a 2.11% by weight mercaptan content, a 1.66% by weight hydroxyl content, and a 12,000cps. bulk viscosity 27 C. The polymer was compounded in the following, sealant recipe:

Polymer 100 Arochlor 1254 50 Zinc oxide 15 RG 244 8.

DMP-30 1.2 Epon 828 11.5

1 A fibrous asbestos filler.

The sealant had a tack-free surface afterv 3 days at, room temperature, and a durometer handness of 40.

The above formulations are useful as caulks for filling cracks and crevices between stone, brick, and concrete, or as a sealant for aluminum, steel, and concrete to glass junctions. Other formulations of the defined hydroxylcontaining liquid mercaptan-terminated polymer yield useful potting compounds in which electrical wires or components may be embedded to provide flexible support, or as flexible adhesives for wood to wood junctions.

I claim:

1. A liquid alkyl acrylate polymer, having a glass transition temperature of below -26 0, containing about 0.1 percent to about 10 percent by weight of pendant hydroxyl groups derived from interpolymerized units of a monomer selected from the group consisting of methylallyl alcohol, hydroxybutyl vinyl ether, orthovinyl benzyl alcohol, metavinylbenzyl alcohol, paravinyl benzyl-alcohol, and the structure wheerin R" is hydrogen or methyl and R' is selected from the group consisting of a radical of the formula C H wherex equals 2 to 10, an ether, a thioether and a ketone wherein the total number of carbonatoms doesnot exceed 10 and about 0.5 percent to about 10 percent by weight of terminal mercaptan groups, both weights based upon the'total weight of polymer.

2. A liquid polymer comprising (1), about 32 percent to. about 96-percent by weight ofan polymerized alkyl acrylate. of the formula wherein R is H, CH or C H and R is selected from the group consisting of alkyl radicals containing 1 to 18 carbon atoms and an etherradical wherein the total number of carbon atoms does not exceed 5, (2) about 3 percent to about 60 percent by weight of the polymerized vinylidene reaction product of (a) an epoxide-containing vinylidene monomer selected from the group consisting of glycidyl acrylate,.glycidyl methacrylate, glycidyl crotonate, allyl glycidyl ether, methallyl glycidyl ether, and isopropenyl glycidyl ether and (b) an alcohol selected from the group consisting of (i) R-OH wherein R is an alkyl, ether, thioether, or ketone wherein the total number of carbon atoms does not exceed 5, and (ii) wherein R is selected from the group consisting of a radical of the formula C H where x=1 to 10, an ether, thioether, and ketone wherein the total number of car- 'bon atoms does not exceed 10, and n is to 10, and (3) from about 0.5 to about 8 percent by weight of mercaptan groups, all weights based upon the total weight of the polymer.

3. A liquid polymer of claim 1 comprising about 32 percent to about 96 percent by weight of polymerized alkyl acrylates of the formula wherein R is -H, CH or C H and R is selected from the group consisting of alkyl groups containing 1 to 18 carbon atoms and an ether group wherein the total number of carbon atoms does not exceed 5, about 3 percent to about 60 percent by weight of the polymerized structure wherein R is H or --CH and R' is selected from the group consisting of a radical of the formula C H where x is 2 to 10, an ether, a thioether, and a ketone wherein the total number of carbon atoms does not exceed 10, thereby having a hydroxyl content of from about 0.1 percent to about percent by Weight, and a mercaptan content of about 0.5 to about 8 percent by weight, all weights based upon the total weight of the polymer.

4. A polymer of claim 3 wherein R" is -H and R is C H where x is 2 to 10.

5. A polymer of claim 4 containing about 1 percent to about 53 percent by weight of polymerized ethyl acrylate and about 14 percent to about 95 percent by weight of a polymerized alkyl acrylate of claim 4 wherein R is H and R is an alkyl group containing 3 to 10 carbon atoms.

6. A polymer of claim 5 wherein x is 4, and the hydroxyl content is from about 0.5 percent to about 5 percent by weight.

7. A polymer of claim 1 in a cured state.

8. A process for preparing a liquid polymer having a glass transition temperature of below 26 C., a hydroxyl content of from about 0.1 to about 10% by weight and a mercaptan content of about 0.5% to about 8% by weight, all weights based upon the total weight of the polymer comprising (a) polymerizing together, in a free radical polymerization, 100 parts by weight of an acrylate of the formula wherein R is --H, --CH or --C H and R is selected from the group consisting of an alkyl radical containing 1 to 18 carbon atoms and an ether radical wherein the total number of carbon atoms does not exceed 5 and from about 2 parts to about 20 parts by weight of a vinylidene monomer containing a hydroxyl group of the formula wherein R is -H or -CH and R'" is selected from the group consisting of a radical of the formula C H where x is 2 to 10, an ether, thioether and a ketone radical wherein the total number of carbon atoms does not exceed 10,

10 in the presence of about 2 to about 20 parts by weight of a dixan'thogen disulfide of the formula s s R-O- -s-sr io-R where R is an alkyl radical of 3 to 6 carbon atoms, thereby preparing a xanthate-terminated polymer, (b) heating the xanthate-terminated polymer of step (a) at a temperature from about 130 C. to about 260 C. under a vacuum, and (c) recovering the polymer.

9. A process of claim 8 wherein the acrylate monomer R is -H and R is an alkyl group containing 3 to 8 carbon atoms, in the dixanthogen disulfide R is a diisopropyl radical, in the alcohol R is C I-I Where x is l and n is equal to 4, and the mineral acid is hydrochloric acid.

10. A process for the preparation of a liquid polymer having a glass transition temperature of below 26 C., a hydroxyl content of from about 0.1 to about 10 percent by weight, and a mercaptan content of from about 0.5 percent to about 8 percent by weight, comprising (1) polymerizing together in a free radical polymerization, parts by weight of an alkyl acrylate of the formula wherein R is -H, -CH or C H and R is selected from the group consisting of an alkyl radical containing 1 to 18 carbon atoms and an ether radical wherein the total number of carbon atoms does not exceed 5 and from about 2 to about 20 parts by weight of the vinylidene reaction product of (a) a vinylidene monomer containing an epoxide group selected from the group consisting of glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, allyl glycidyl ether, methallyl glycidyl ether, and isopropenyl glycidyl ether with (b) an alcohol selected from the group consisting of (i) monohydroxy alcohols of the formula R-OH wherein R is selected from the group consisting of alkyl, ether, thioether, and ketone radicals where the total number of carbon atoms does not exceed 5, and (ii) a polyhydric alcohol of the formula wherein R is selected from the group consisting of a radical of the formula C H where x=1 to 10, an ether, thioether, and a ketone where the total number of carbon atoms does not exceed 10, and n is 0 to 10, in the presence of from about 2 to about 20 parts by weight of a dixanthogen disulfide of the formula CHz-OH References Cited UNITED STATES PATENTS 6/1969 Noll et a1. 26079 5/1971 Siebert 204-159.24

MAURICE J. WELSH, Primary Examiner M. I. MARQUIS, Assistant Examiner U.S. Cl. X.R.

161203, 204, 216, 218, 247, 256; 204-159.18, 159.24; 260-41 A, 41 B, 41 AG, 77.5 CR, 79.5 R, 79.5 C, 89.5 S, 830 S UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION P atentv No. 3 711 451 Dated January 16 1 973 lnven razc Alan- A. Csontos I It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 10, after "amounts" insert- 01 these monomers used are in the range of from about; line 28, "polymesr" should read --polymers--; line 68, "and" first occurrence,

should read --to--.

Column 3, line 3, after"onitrile,-" insert '--metaacrylonitrile--'; line 16, "glycidy" should read --glycidyl--.

Column 5, lines +5 to 50, the formulashould read as follows:

--CH 3H-- I I v OCH CHCH OR' 'OH v Column 7, line 59, in the table, "DMP-O should read---DMP-30 Column 8, line'52, "wheerin" should read --wherein--. I I

Column 9, line n3, Claim 5, "1 should read 13--.

Signed and sealed this 9th day of April 1971 (SEAL) Attest:

EDWARD I LFLETCHERJR. O. MARSHALL DANN Attesting Officer Commissioner of Patents FOQM -1050(0-69 PO I v USCOMM-DC 60376-P69 a U.S. GOVERNMENT PRINTING OFFICE: l9! 0-366-33l 

